Domestic, house-broken animals, particularly cats, are typically trained to urinate and defecate in a specially provided litter box. Consequently, pet owners, homeowners, veterinarians and laboratory personnel have added absorbent materials to the litter box to collect the urine and feces (i.e., dross). A major problem with the absorbent materials is that after a relatively short period of time, the dross soiled absorbent emits objectionable odors due to the presence of the urine and fecal matter.
In order to reduce or eliminate these objectionable odors, homeowners periodically remove the fecal matter from the absorbent material(s). However, physical removal of the feces does not reduce or eliminate odors caused by the urine absorbed into the absorbent. Therefore, when the odors caused by the absorbed urine become intolerable, the homeowner discards the absorbent material. The homeowner then washes the litter box and refills it with fresh absorbent material. These activities are, however, unpleasant, time-consuming and expensive.
The most commonly used absorbent materials are inexpensive clays, such as calcined clays, that are safe and non-irritating to the animals. As is well known in the art, clays generally absorb relatively substantial amounts of liquids.
Other porous absorbent materials, that are used alone or in combination, include straw, sawdust, wood chips, wood shavings, porous polymeric beads, shredded paper, bark, cloth, ground corn husks, cellulose, water-insoluble inorganic salts, such as calcium sulfate, and sand. Although the noted absorbent materials have the advantage of low cost, each suffers from the disadvantage of merely absorbing and retaining the liquid dross within its porous matrices, or, in the case of sand, absorbing the liquid dross on its surface.
More recently, litter compositions having bentonite clay particles have been employed to address the malodor problem arising from retained urine and fecal matter. As is well known in the art, bentonite is a water-swellable clay which, upon contact with liquid (or moist) dross, readily agglomerates with other moistened bentonite clay particles. The moist animal waste is thus isolated by the agglomeration of the moist clay particles and can be readily removed from the litter. Illustrative bentonite based litter compositions are disclosed in U.S. Pat. Nos. 5,503,111, 5,386,803, 5,317,990, 5,129,365 and U.S. Reissue Pat. No. RE 33, 983.
Various other litter compositions and techniques have also been employed to address the malodor problem arising from the presence of urine and fecal matter, particularly urine. For example, U.S. Pat. Nos. 3,059,615, 3,029,783, 4,306,516 and 3,892,846 teach the use of fairly strong inorganic or organic acids to control ammonia formation and, hence, offensive odors.
Still others have sought to decrease odors by employing a non-clay substrate to improve the absorption rate of the litter composition. Illustrative is the alfalfa-based litter composition disclosed in U.S. Pat. No. 3,923,005. However, the simple change of substrate limits the litter composition to the particular substrate's absorptive capacity.
Unlike other prior art attempts, which merely use a clay or absorbent plant material, U.S. Pat. No. 5,970,915 teaches the use of a macroporous silica gel in granular form as the litter substrate. Odor reduction is, however, primarily addressed by applying a film of a disinfectant to the inside surface of the litter box.
A further drawback of the litter composition disclosed in the '915 patent, and each of the aforementioned litter compositions, is the permeation of urine through the litter composition, which accumulates at the bottom of the litter box. After a brief period of time, the accumulated urine decomposes, produces volatile compounds (e.g., ammonia) and, ultimately, emits offensive odors.
It is therefore an object of the present invention to provide an improved litter composition that overcomes the aforementioned drawbacks and disadvantages that are often associated with conventional litter compositions.
It is another object of the invention to provide a low cost, litter composition that substantially reduces the emanation of offensive odors from urine and fecal matter disposed therein.
It is another object of the invention to provide a litter composition that readily agglomerates upon contact with moist dross and, hence, facilitates removal of the dross from the composition.
It is yet another object of the invention to provide a litter composition that substantially reduces liquid dross permeation to the bottom of the litter box.